1. Field of the Invention
This invention relates to switchgear assemblies and particularly to a switchgear assembly in which removable covers are provided over access openings in the doors of the cells within the switchgear cabinet in which electrical apparatus such as circuit breakers are housed.
2. Background Information
Switchgear assemblies for electric power distribution systems include electrical apparatus housed in metal cabinets with associated conductors, including bus bars and cabling, for connecting the electrical apparatus in appropriate locations within the distribution system. Typically, the electrical apparatus includes switching devices such as circuit breakers or network protectors which provide protection, disconnect switches for isolating parts of the distribution system, and transfer switches for connecting the distribution system to alternative power sources. The electrical apparatus can also include instrumentation such as metering equipment.
In a common arrangement, the electrical apparatus is installed in vertically stacked cells within the cabinet. Each of the cells has a separate door in front of the cabinet through which the electrical apparatus is inserted and removed. Due to the weight and bulk of the electrical apparatus, the cells contain a roll-out carriage on which the electrical apparatus is supported. As the electrical apparatus is rolled into the cell, quick disconnects on the rear face of the electrical apparatus engage stabs which connect the electrical apparatus to the appropriate buses of the distribution system.
In a common arrangement, the cell doors are provided with access openings through which the front face of the electrical apparatus projects for control and monitoring of the electrical apparatus without the need to open the cell door. With such an arrangement, when the electrical apparatus is removed from the cell, or not all of the cells are utilized, the interior of the empty cell is exposed through the access opening which is typically quite large. As the cell contains conductors energized at the system primary voltage, this is not a satisfactory condition. It has been necessary in the past to replace the door with the access opening with a solid front door under these conditions.
There is a need, therefore, for an improved switchgear assembly having cell doors with access openings that prevents access to an empty cell without requiring the replacement of the cell door.
There is a related need for such an improved switchgear assembly that provides for blocking the access opening in the door of an empty cell simply and quickly and without the need for tools.